Buks, you can buy them in Curry's, John Lewis etc etc or of course on the net.
I've had a Paperwhite for years now and it performs as well as ever. As has been said above, the latest version is slightly slimmer than mine and is waterproof (not that I take mine swimming).
Do get a decent leather cover (about 30 GBP) as it has a sleep function and obviously protects the screen. The device should cost about 100 GBP.
As far as downloading is concerned, just use your usual/favourite torrent sites. Pirate Bay is still good and another that sometimes gives more seeders is
https://1337x.to/ although I rarely find something on there that isn't on PB and downloads are small and quick anyway.
As far as formats are concerned, the Kindle is compatible with MOBI but most books these days are EPUB. However, just use an ebook management system. I use
https://calibre-ebook.com/ and it'll convert format to format automatically. Easy. It'll also retain your library if you need to delete stuff from the Kindle. The only format I don't like is PDF files. In my experience, they come out badly formatted and in gibberish.
For inspiration, after I exhausted all my favourite author's book, I now simply search for best sellers a few times a month, read reviews and then decide whether to download. I'll pretty much guarantee that a best seller will be downloadable within days. I link to newspapers' book columns etc etc. That's just ideas.
You won't go wrong with a Kindle. I also love the "feel" of a book but hell when I've got one of largest free libraries on hand through torrent sites - well, what can I say?
Together with my golf clubs and computer, I'd be lost without the Kindle now. And I don't know how the first two work.
PS, the thing is that you don't have to use Amazon. You maybe won't be able to access the torrent sites in the UK but Amazon do have loads of free books that have gone out of copywrite. So, if you can get by with Dickens, Austen, Conrad, Kafka etc etc, do so and fill your boots when you get back here.
Oh yeah, it was your good self that advised me years ago just to leave the device in aeroplane mode so the gits won't know what I'm doing. Just like leaving MS updates off. The Amazon internet thing is a con.